Least Common Multiple of 8 and 18

Least common multiple or lowest common denominator (LCD) can be calculated in three ways;

• Least Common Multiple of 8 and 18 by Prime method
• Least Common Multiple of 8 and 18 with GCF Formula

Least common multiple can be found by multiplying the highest exponent prime factors of 8 and 18. First we will calculate the prime factors of 8 and 18.

Prime Factorization of 8

Prime factors of 8 are 2. Prime factorization of 8 in exponential form is:

8 = 2³

Prime Factorization of 18

Prime factors of 18 are 2,3. Prime factorization of 18 in exponential form is:

18 = 2¹×3²

Now multiplying the highest exponent prime factors to calculate the LCM of 8 and 18.

LCM(8,18) = 2³×3²
LCM(8,18) = 72

Factors of 8

List of positive integer factors of 8 that divides 8 without a remainder.

1, 2, 4, 8

Factors of 18

List of positive integer factors of 18 that divides 18 without a remainder.

1, 2, 3, 6, 9, 18

The formula of LCM is LCM(a,b) = ( a × b) / GCF(a,b).
We need to calculate greatest common factor 8 and 18, than apply into the LCM equation.

GCF(8,18) = 2
LCM(8,18) = ( 8 × 18) / 2
LCM(8,18) = 144 / 2
LCM(8,18) = 72

(i) The LCM of 18 and 8 is associative

LCM of 8 and 18 = LCM of 18 and 8

1. What is the LCM of 8 and 18?

Answer: LCM of 8 and 18 is 72.

2. What are the Factors of 8?

Answer: Factors of 8 are 1, 2, 4, 8. There are 4 integers that are factors of 8. The greatest factor of 8 is 8.

3. What are the Factors of 18?

Answer: Factors of 18 are 1, 2, 3, 6, 9, 18. There are 6 integers that are factors of 18. The greatest factor of 18 is 18.

4. How to Find the LCM of 8 and 18?

Answer:

Least Common Multiple of 8 and 18 = 72

Step 1: Find the prime factorization of 8

8 = 2 x 2 x 2

Step 2: Find the prime factorization of 18

18 = 2 x 3 x 3

Step 3: Multiply each factor the greater number of times it occurs in steps i) or ii) above to find the lcm:

LCM = 72 = 2 x 2 x 2 x 3 x 3

Step 4: Therefore, the least common multiple of 8 and 18 is 72.